package cn.lili.common.utils;

import lombok.extern.slf4j.Slf4j;
import org.springframework.web.multipart.MultipartFile;

import java.io.*;
import java.util.Base64;
import java.util.Base64.Decoder;

/**
 * base64转为multipartFile工具类
 *
 * @author Chopper
 */
@Slf4j
public class Base64DecodeMultipartFile implements MultipartFile {

	private final byte[] imgContent;
	private final String header;

	public Base64DecodeMultipartFile(byte[] imgContent, String header) {
		this.imgContent = imgContent;
		this.header = header.split(";")[0];
	}

	@Override
	public String getName() {
		return System.currentTimeMillis() + Math.random() + "." + header.split("/")[1];
	}

	@Override
	public String getOriginalFilename() {
		return System.currentTimeMillis() + (int) Math.random() * 10000 + "." + header.split("/")[1];
	}

	@Override
	public String getContentType() {
		return header.split(":")[1];
	}

	@Override
	public boolean isEmpty() {
		return imgContent == null || imgContent.length == 0;
	}

	@Override
	public long getSize() {
		return imgContent.length;
	}

	@Override
	public byte[] getBytes() throws IOException {
		return imgContent;
	}

	@Override
	public InputStream getInputStream() {
		return new ByteArrayInputStream(imgContent);
	}

	@Override
	public void transferTo(File dest) throws IOException, IllegalStateException {
		OutputStream stream = null;
		try {
			stream = new FileOutputStream(dest);
			stream.write(imgContent);
		} catch (IOException e) {
			log.error("transferTo错误", e);
		} finally {
			assert stream != null;
			stream.close();
		}
	}

	public static MultipartFile base64Convert(String base64) {

		String[] baseStrs = base64.split(",");
		Decoder decoder = Base64.getDecoder();
		byte[] b = decoder.decode(baseStrs[1]);

		for (int i = 0; i < b.length; ++i) {
			if (b[i] < 0) {
				b[i] += 256;
			}
		}
		return new Base64DecodeMultipartFile(b, baseStrs[0]);
	}

	public static InputStream base64ToInputStream(String base64) {
		ByteArrayInputStream stream = null;
		try {
			byte[] bytes = Base64.getDecoder().decode(base64);
			stream = new ByteArrayInputStream(bytes);
		} catch (Exception e) {
			log.error("base64ToInputStream错误", e);
		}
		return stream;
	}

	public static String inputStreamToStream(InputStream in) {
		byte[] data = null;
		// 读取图片字节数组
		try {
			ByteArrayOutputStream swapStream = new ByteArrayOutputStream();
			byte[] buff = new byte[100];
			int rc = 0;
			while ((rc = in.read(buff, 0, 100)) > 0) {
				swapStream.write(buff, 0, rc);
			}
			data = swapStream.toByteArray();
		} catch (IOException e) {
			log.error("转码错误", e);
		} finally {
			if (in != null) {
				try {
					in.close();
				} catch (IOException e) {
					log.error("inputStreamToStream错误", e);
				}
			}
		}
		return Base64.getEncoder().encodeToString(data);
	}
}
